The following relates generally to wireless communications, and more specifically to reference signal transmission based on received signal quality.
Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems, (e.g., a Long Term Evolution (LTE) system). A wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).
Wireless communication systems conventionally rely on various reference signals (RSs) to determine various channel conditions. Examples of RSs may include, but are not limited to, cell specific RSs, UE specific RSs, positioning RSs, channel state information (CSI) RSs, sounding RSs (SRSs), and the like. The RSs may be transmitted by a UE and used by the base station to determine uplink channel quality and/or transmitted by the base station and used by the UE to determine downlink channel quality. Additionally, base stations often allocate a partial section of the available bandwidth for a particular UE at a particular time. Therefore, the RSs may provide an indication of the channel quality for the uplink and/or downlink path for each frequency region (e.g., each channel, tone, bin, etc.).
Conventional techniques may include the base station controlling the RS transmissions of the UE. In one non-limiting example, SRS transmissions from the UE may be controlled by the base station or evolved NodeB (eNB). Depending on the UE capability, the base station may trigger the SRS transmission from a single UE antenna or from multiple antennas of the UE. Multiple antennas may be sounded (e.g., used for SRS transmission) simultaneously (e.g., in a multiple-input/multiple-output (MIMO) mode) or one at a time (e.g., using transmission antenna switching). Such conventional techniques, however, may not provide an opportunity for the UE to provide input regarding which antennas are used for SRS transmission.